Moyamoya disease

Aneesh B Singhal MD (

Dr. Singhal of Harvard Medical School received consulting fees from Deck Therapeutics and Omniox, and his wife is an employee and owns stock in Biogen.

Eva A Rocha MD (

Dr. Rocha of Universidade Federal de São Paulo has no relevant financial relationships to disclose.

Steven R Levine MD, editor. (

Dr. Levine of the SUNY Health Science Center at Brooklyn has no relevant financial relationships to disclose.

Originally released September 18, 1995; last updated April 1, 2020; expires April 1, 2023

This article includes discussion of Moyamoya disease, cerebral arterial rete, cerebral basal rete mirabile, cerebral juxtabasilar telangiectasia, hypoplasia of the internal carotid artery, idiopathic progressive occlusive disease of the circle of Willis, Nishimoto disease, rete mirabile, spontaneous occlusion of the circle of Willis, and Moyamoya phenomenon. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.


In this article, the authors provide a comprehensive overview of moyamoya disease, including advances in the genetics and molecular biology of moyamoya disease, the role of newer imaging techniques, and the surgical management of moyamoya disease.

Key points


• Moyamoya disease is an idiopathic non-atherosclerotic vasculopathy with characteristic angiographic abnormalities involving the terminal internal carotid artery and its branches.


• Similar angiographic changes have been associated with diverse conditions, including neurofibromatosis, craniopharyngioma, Down syndrome, sickle cell disease, Graves disease, and the use of vasoconstrictive drugs such as cocaine.


• Patients can be asymptomatic or present with ischemic or hemorrhagic strokes. Other manifestations include intellectual dysfunction, seizures, and movement disorders.


• Early surgical intervention (eg, encephalo-duro-arterio-synangiosis) before the establishment of irreversible hemodynamic change appears to be effective in preventing complications from progressive arterial stenosis and collateral formation.

Historical note and terminology

Moyamoya disease is a nonatherosclerotic and noninflammatory condition characterized by progressive stenosis of the terminal internal carotid artery and the proximal portions of the anterior cerebral and middle cerebral arteries (Kuroda and Houkin 2008; Scott and Smith 2009). The disease is usually bilateral but can be unilateral. It may begin as an asymptomatic isolated stenosis of the middle cerebral artery stem, progressing to symptomatic moyamoya disease over a few years (Choi et al 2007). The term "moyamoya disease" is used when the internal carotid artery stenoses and associated collaterals are observed and when no associated diseases are identified. "Moyamoya phenomenon" is used to describe the extensive collateralization of the circle of Willis arteries associated with severe unilateral or bilateral internal carotid artery stenosis or occlusion in the presence of conditions such as sickle cell disease, atherosclerosis, cranial irradiation, and neurofibromatosis. Synonyms include "idiopathic progressive occlusive disease of the circle of Willis," "spontaneous occlusion of the circle of Willis" (Kudo 1968) "cerebral basal rete mirabile," and "cerebral juxtabasilar telangiectasia."

The history of moyamoya disease is fascinating. Shimizu and Takeuchi published the first case of moyamoya disease in 1957(Shimizu and Takeuchi 1957). Suzuki was the first to use the Japanese term "moyamoya" to describe the hazy, cloudy “puff of smoke” appearance of the network of dilated, abnormal microvasculature occurring in the region of the circle of Willis (Suzuki and Takaku 1969). These authors also described the six stages of angiographic progression, from stage 1 (narrowing of the carotid artery) to stage 6 when moyamoya vessels disappear and the external carotid arteries supply collateral flow. In 1964, Nishimoto published a series of 24 cases, including three new cases and 21 cases from the literature. The first autopsy report by Maki in 1965 demonstrated a narrowing of the lumen of the internal carotid artery, with intimal thickening but no abnormality of the media or adventitia and no inflammatory changes (Maki and Nakata 1965). In 1967, the proceedings of the Japan Neurosurgical Society were published and included a discussion of moyamoya disease (Kudo 1967). In 1968, Kudo published 12 cases and proposed that the dilated penetrating arteries represented an attempt to form collaterals in response to progressive occlusion of the main affected arteries (Kudo 1968). The same year, Nishimoto published a collection of 96 cases (Nishimoto and Takeuchi 1968); therefore, the disease is sometimes referred to as “Nishimoto disease” or “Nishimoto-Takeuchi-Kudo disease.”

In 1977 the Research Committee on Moyamoya Disease organized by the Japanese Ministry of Health and Welfare proposed the following features in the angiographic definition of moyamoya disease: (1) stenosis or occlusion of the terminal portions of both internal carotid arteries and the proximal portions of the anterior cerebral and middle cerebral arteries; (2) visualization of abnormal vascular networks during the arterial phase in the vicinity of the occlusions; and (3) the absence of diseases that may be associated with the development of the moyamoya phenomenon, including meningitis, atherosclerosis, radiation, neurofibromatosis, Down syndrome, sickle cell disease, and neoplasms. In the case of unilateral typical angiographic changes and in the absence of the previously mentioned associated conditions, the case may be classified as probable (Gotoh and Nakahara 1978).

Tavares reported the first non-Japanese cases in 1969 (Tavares 1969). He described 10 cases and discussed the three major collateral pathways: (1) the circle of Willis, (2) leptomeningeal arteries, and (3) transdural vessels. Since Tavares' report, cases have been reported from all over the world. Large single and multicenter co-operative studies have described the clinical features of patient populations from various countries, including the United States, and have highlighted differences between Caucasians and Eastern populations (Chiu et al 1998; Yilmaz et al 2001; Kraemer et al 2008; Guzman et al 2009; Miao et al 2010; Bower et al 2013; Han et al 2014).

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